The present invention relates generally to dynamic algorithm selection to accomplish volume rendering along with isocontour and body extraction within a multiple-instruction, multiple-data multiprocessor.
Previous techniques for accomplishing volume rendering within a 3D volume require complete examination of the volumes in order to perform a correct volume rendering. This technique imposes a great computational workload, and there was a need for reducing this workload.
United States patents of interest which relate to imaging systems for three-dimensional displays include U.S. Pat. No. 4,882,679, to Tuy et al, U.S. Pat. No. 4,821,210, to Rumbaugh, U.S. Pat. No. 4,697,178, to Heckel, and U.S. Pat. No. 4,685,070, to Flinchbaugh.
In particular, the Tuv et al patent describes a system for three-dimensional diagnostic imaging, in which a plurality of slice images of a specimen are generated. A region of interest is selected from within a slice, and is extrapolated to subsequent slices. A boundary, indicative of a surface of interest, is selected from within the region of interest. A viewing surface is defined in relation to a generated surface image which was selected from the boundary. A scaling means assigns a scaled gray level to the three-dimensional image. Image information is selectively modified by the data from the original slice images to add surface density visualization. Means is also provided to facilitate selective segmentation of a three-dimensional image along a plane or planes of interest.
The Rumbaugh patent relates to a system and method for the fast display of three-dimensional images. A plurality of volumetric cells containing three-dimensional image information are scanned onto a two-dimensional viewplane. The cells are organized to conjointly represent a volume by arranging them contiguous to each other and forming a plurality of parallel, planar arrays. The cells are sequentially displayed by planar arrays starting with the array most distant from the viewplane and proceeding to the array closest to the viewplane. Within each displayed array, the cells are displayed in back-to-front order by rows starting with the row most distant from the viewplane and proceeding to the row closest to the viewplane. Within each row, the cells are displayed in order of decreasing distance from the viewplane. Finally, the polygonal surfaces within the cells are displayed.
The Heckel patent describes a computer graphics system for real time calculation and display of the perspective view of three-dimensional scenes. Hidden lines and surfaces are removed from the display at high speed in a hardware raster processor which uses a scan line depth buffer algorithm. The algorithm minimizes computation time by utilizing a line segment analysis of the scene to be displayed in which only the depth information for each pixel within each line segment within each line to be scanned is compared with depth information of the corresponding pixel in a depth buffer (z-buffer). The display information and depth information of each pixel is stored in the depth buffer only when the depth information of the pixel being compared with the corresponding depth information in the depth buffer lies closer to the view reference plane. The storage of display information of only pixels closer to the view reference plane than the stored display information minimizes time-consuming storage of information and the amount of memory required.
The Flinchbaugh patent relates to a system for displaying and interactively examining a three-dimensional volume. A computer system is utilized to display in two dimensions a representation of a three-dimensional volume, which is a tessellation of cells represented as three-dimensional units. The three-dimensional volume is represented by a plurality of digital numbers, and a designator determines which of the digital numbers are to be represented in the two-dimensional display. Each digital number is represented by one cell, and represents a color which indicates a parameter such as amplitude. Each corresponding cell is colored in accordance with the digital number. A cursor may be used to indicate which of the three-dimensional volume representations is to be excavated. The designator is thereby changed, and the excavated cells are stripped away, exposing the immediately adjacent cells.
Other publications of interest include:
Frieder, G.; Gordan, D.; and Reynolds, R. A. "Back-to-Front Display of Voxel-Based Objects," IEEE Computer Graphics and Applications, vol. 5, no. 1, pp. 52-60, January, 1985.
Reynolds, Richard A. "Fast Methods for 3D Display of Medical Objects", Ph.D. Dissertation, Dept. of Computer and Information Science, University of Pennsylvania, May, 1985, 257 pp.
Reynolds, R. Anthony; Gordan, Dan; and Chen, Lih-Shyang, "A Dynamic Screen Technique for Shaded Graphics Display of Slice-Represented Objects, Computer Vision, Graphics, and Image Processing", vol. 38, no. 3, pp. 275-298, June, 1987.